Early Cambrian Brain

Early Cambrian brain described in ScienceShots 16 October 2012 and ABC News in Science 17 October 2013. Scientists have used a computed tomography (CT) scanner to study the brain and nervous system of a small crustacean-like fossil found in the Chengjiang formation in Yunnan province in southwestern China. According to ABC article, “the animal belongs to the megacheirans, a group of clawed marine animals that lived during the Cambrian, a time of riotous biodiversity”. The creature had an elongated body consisting of 11 segments with leg-like appendages. It also had four eyes and a long claw projecting from its head, which may have been used for sensing or grasping. The CT scan revealed the structure of its optic nerves, brain and ganglia (nervous tissue outside the brain). Its nervous system is most similar to a group of modern-day arthropods known as chelicerates, which includes spiders, scorpions, and horseshoe crabs.

According to ScienceShots: “The finding clears up the picture of the arthropod family tree, which is particularly important because some of these creatures’ features were so unlike those of their presumed kin.” One of the research team, Nicholas Strausfeld, a neuroscientist at the University of Arizona commented: “We now know that the megacheirans had central nervous systems very similar to today’s horseshoe crabs and scorpions. This means the ancestors of spiders and their kin lived side by side with the ancestors of crustaceans in the Lower Cambrian”.

Editorial Comment: The problem of different creatures possessing similar nervous systems, but being otherwise “so unlike their presumed kin” is solved if you remember that living creatures were a) created as separate kinds, and b) each kind is a unique combination of non-unique parts. Therefore, animals can have similar nervous systems, but have other features that are different. The fact that living creatures such as horseshoe crabs, spiders and scorpions have nervous systems like this fossil creature, just shows that this nervous system works well. Furthermore it has not changed since this animal was buried, no matter how old you believe this extinct creature or the ancestors of horseshoe crabs are. Horseshoe crabs and scorpions are classic examples of living fossils – creatures whose fossils are the same as their living descendant, which means they have not evolved, but have multiplied after their kind.

The description of the Cambrian being “a time of riotous biodiversity” is a reminder the fossil record contains enormous numbers of intriguing creatures, such as this megacheiran, that have now become extinct. These serve as a reminder that the real history of the world is that it started out good, filled with many wonderful, fully formed creatures living together in functioning ecosystems, but this, sadly, has since become degraded by human sin and God’s judgement. The fossil record is not the history of life – it is the record of death in the world. (Ref. crustaceans, invertebrates, neurology)